Field of the Invention
In one form, the invention hereof presents a retrofit device for supplementing a legacy flow meter with a digital interface for control and data transmission. A primary embodiment of the invention includes a retrofit device for a legacy turbine flow meter used in a pipe system. Aside providing a digital interface, the presented retrofit device enhances the function of the legacy flow meter by adding means for error diagnostics and tamper detection. The presented design also solves various challenges arising from the requirement to adapt the retrofit device to the mechanical and casing form factor design of the legacy flow meter, particularly a flow meter already installed, such as buried in the ground.
Description of the Relevant Art
Many industrial or technical installations contain a substantial number of measurement or control devices that function on a purely mechanical basis. In many such installations a measurement or control device may have a part of its function realized by electrical or electronic components, but its capabilities for remote control or digital transmission of data are inadequate for integration into modern management systems, such as for centralized control, accounting, or data mining.
The term legacy device in general is applied herein to devices in industrial or technical installations, that are primarily mechanical and often do not accommodate recent technical advancements, or contemporary requirements. Typically, this means such installations are not enabled with a digital interface or with an outdated one, which prevents integration of them into modern systems for networking, automation, and data management. Legacy devices abound in industrial and technical installations, for instance in mining, agriculture, transport, or a utility system in an urban area. Examples of legacy devices are mechanical valves, flow or pressure meters, levers or shutoff devices in pipe installations, or recording devices for environmental data that function on a purely mechanical basis.
Such legacy devices ideally would be upgraded to newer designs, equipped with a digital interface and enabled for remote control, yet often there are outweighing reasons for their replacement. Such legacy devices often have a complex, mature design that is proven in terms of reliability and longevity. Also, replacing a legacy device with a new one that is digitally enabled and has equal functionality may not be economical to do. Aside from design and production costs, the expense of replacing a legacy device in a technical installation may be considerable. For instance, exchanging a flow meter or pressure valve in a pipe system may require a complete shutoff of large sections of the pipe infrastructure and be a substantial manual labor effort. Further, a legacy device may not be upgraded for reasons of compliance with safety or other standards, if a standards qualification is costly or nor a priority for a regulatory body.
Notwithstanding reasons to keep legacy devices in place, there are compelling reasons for their digital enablement, for remote control, monitoring and data transmission. For example, equipping flow meters in a pipe installation for remote, real time data collection provides new uses and diagnostic capabilities for the pipe system. For instance, by means of simultaneous data collection, leaks in the pipe system may be detected. Also, obtaining real-time usage data in a residential water supply infrastructure would allow for billing system with rates depending on the time of day.
Though desirable, retroactively equipping a legacy device for digital monitoring and data transmission has many challenges. Such design has many requirements, posed by the existing installation in terms of form factor and function. For instance, there are limitations in the placement of sensors, typically required for enabling a device with mechanical parts with a digital interface. A design to retrofit a legacy device for digital enablement often has the requirement that the enclosure of the legacy device cannot be opened or tampered with, or its mechanical parts not be affected in any manner. Also, the retrofit of a device with a digital interface should not obstruct the uses that device has been designed for.